- Enantiospecific synthesis of substituted 1-norbornyl trifluoromethanethiosulfonates and 1-norbornanethiols
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New homochiral 1-norbornylthiotriflates 6 and 7 and 1-norbornanethiols 8 and 9 are easily prepared starting from naturally occurring 2-norbornanones 1. The key step is the reaction of chiral 2-norbornanethiones 2 with Tf2O under mild conditions.
- Martinez, Antonio Garcia,Vilar, Enrique Teso,Jimenez, Florencio Moreno,Bilbao, Carlota Martinez
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- Reactions of cycloaliphatic thioketones and their Oxo analogues with lithiated methoxyallene: A new approach to vinylthiiranes
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Admantanethione smoothly reacted with lithiated methoxyallene at low temperatures yielding the expected allenyl-substituted thiolate, which upon aqueous work-up underwent spontaneous 1,3-cyclization to afford a hitherto unknown methoxy-substituted vinylth
- Jasiński, Marcin,Mlostoń, Grzegorz,Stolarski, Micha?,Costa, Wilhelmine,Domínguez, Moises,Reissig, Hans-Ulrich
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- Formation of kinetically stabilized dithiiranes by treating thione S-oxides bearing a bulky substituent with Lawesson's reagent
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Treatment of sterically crowded thione S-oxides derived from d-camphor with Lawesson's reagent afforded dithiiranes along with deoxygenation of the starting materials, and the mixtures were subjected to mCPBA oxidation to give the corresponding dithiirane S-oxides and thione S-oxides.
- Shimada, Kazuaki,Kodaki, Keiichi,Aoyagi, Shigenobu,Takikawa, Yuji,Kabuto, Chizuko
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- Photochemical Oxidation of Thioketones by Singlet Molecular Oxygen Revisited: Insights into Photoproducts, Kinetics, and Reaction Mechanism
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Photosensitized oxidation of trimethyl[2.2.1]bicycloheptane thioketones by 1O2 can yield more photoproducts than exclusively ketones and sulfines. Moreover, the ketone/sulfine ratio can be reversed when protic conditions and high thioketone concentrations are used, conversely to earlier results reporting ketones as the main photoproducts. A new mechanistic proposal for sulfine formation is suggested following intermolecular oxygen transfer from a peroxythiocarbonyl intermediate to a second thioketone molecule. Reaction quantum yields (10-5-10-2) depend on the reaction conditions and time. Sulfine production reaches a maximum at short irradiation times, whereas decomposition to the corresponding ketone is observed at long reaction times. When the thioketone substrate has a hydrogen atom at the α position a peroxyvinylsulfenic acid intermediate can be formed by proton transfer. Reaction of this intermediate with another thioketone molecule can yield more sulfine and its tautomeric vinylsulfenic acid, which dimerizes in situ to the thiosulfinate. The hydroperoxyl group of the peroxyvinylsulfenic acid can also rearrange to the α position, and by reaction with the starting thioketone, α-hydroxy thioketone and additional sulfine can be formed, while dehydration yields the α-oxo thioketone. In situ [2 + 2] and [4 + 2] self-cycloaddition of the α-oxo thioketone yields significant amounts of the corresponding adducts at prolonged irradiation times.
- Sánchez-Arroyo, Antonio J.,Pardo, Zulay D.,Moreno-Jiménez, Florencio,Herrera, Antonio,Martín, Nazario,García-Fresnadillo, David
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p. 10575 - 10584
(2015/11/18)
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- Dynamics of capsuleplex formed between octaacid and organic guest molecules - Photophysical techniques reveal the opening and closing of capsuleplex
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This manuscript is concerned with the opening and closing of a capsuleplex made up of organic guest molecules and two cavitand molecules known as octaacid (OA). The capsuleplex is loosely held together in water through weak interactions. We have investiga
- Jayaraj, Nithyanandhan,Jockusch, Steffen,Kaanumalle, Lakshmi S.,Turro,Ramamurthy
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supporting information; experimental part
p. 203 - 213
(2011/04/23)
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- Synthesis of 14C- and 14C3-labelled Org 37462
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Org 37462 (1) is the active ingredient in Orgalutran, an innovative product that reduces the time of treatment in in vitro fertilization from four to less than two weeks. Org 37462 is a synthetic decapeptide containing several amino acids that are unnatur
- Wiegerinck,Hofstede,Sperling,Vader
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p. 195 - 201
(2008/09/20)
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- Expeditious microwave-assisted thionation with the system PSCl 3/H2O/Et3N under solvent-free condition
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(Chemical Equation Presented) A novel thionation protocol for carbonyl compounds, with the system PSCl3/H2O/Et3N has been discovered. Clean, rapid, and efficient synthesis of a variety of thiocarbonyl compounds such as thioamides, thiolactams, thioketones, thioxanthones, and thioacridone can be achieved through this simple and convenient method under solventless condition with microwave irradiation.
- Pathak, Uma,Pandey, Lokesh Kumar,Tank, Rekha
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p. 2890 - 2893
(2008/09/19)
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- Asymmetric induction through metalation of chiral dithioacetals and oxathioacetals
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The work presented in this article consists of synthesis of chiral dithioacetals and oxathioacetals using pure chiral auxiliaries, such as, (+) camphor, (-) menthol, and L-cysteine. Metalation of these chiral dithioacetals and oxathioacetals, followed by nucleophilic addition to benzaldehyde and removal of chiral auxiliary, furnished scalemic mandelic acid with various enantiomeric purities. Copyright Taylor & Francis Group, LLC.
- Zaidi, Javid H.,Gunjial, Naseem Iqbal
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p. 2835 - 2845
(2008/03/11)
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- Synthesis of dithioacetals and oxathioacetals with chiral auxiliaries
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One-pot synthesis of dithioacetals as well as an efficient method for oxathioacetal is reported. Additionally, some chiral auxiliaries were used to synthesize enantiomerically pure dithioacetals and oxathioacetals.
- Zaidi, Javid H.,Naeem, Fazal,Khan, Khalid M.,Iqbal, Rasfaid,Zia-Ullah
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p. 2641 - 2653
(2007/10/03)
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- A new, efficient and simple method for the thionation of ketones to thioketones using P4S10/Al2O3
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A simple, efficient and new method has been developed for the synthesis of thioketones by thionation of ketones using P4S10/Al 2O3 in acetonitrile. It has been found that the P 4S10/Al2O3 combination provides a simple and convenient method for the synthesis of thioketones.
- Polshettiwar, Vivek,Kaushik
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p. 6255 - 6257
(2007/10/03)
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- Bridged bicyclic cores containing a 1,1-diarylethylene motif are high-affinity subtype-selective ligands for the estrogen receptor
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The actions of estrogens are mediated through the two estrogen receptors, ERα and ERβ. Compounds that interact selectively with ERα or ERβ are of interest because they could be used to explore the biological roles of these ER subtypes and they might be in
- Muthyala, Rajeev S.,Sheng, Shubin,Carlson, Kathryn E.,Katzenellenbogen, Benita S.,Katzenellenbogen, John A.
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p. 1589 - 1602
(2007/10/03)
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- Thionation with the reagent combination of phosphorus pentasulfide and hexamethyldisiloxane
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The combination of P4S10 and hexamethyldisiloxane efficiently converts esters, lactones, amides, lactams, and ketones to their corresponding thiono derivatives. In the presence of elemental sulfur, 3-oxoesters are converted to dithiolethiones by this reagent. Yields are comparable to or superior to those obtained with Lawesson's reagent. The method has the advantage that reagent-derived byproducts may be removed by a simple hydrolytic workup or by filtration through silica gel, rather than by chromatography, as required for Lawesson's reagent.
- Curphey, Thomas J.
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p. 6461 - 6473
(2007/10/03)
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- Studies on the preparation of camphorylidene derivatives of α-amino acids
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An improved method has been developed for the efficient synthesis of stable camphor imine salts. Camphor imine readily undergoes transimination with α-amino acid ester hydrochlorides to yield camphorylidene amino acid derivatives with E stereochemistry about the C=N double bond. Sodium cyanoborohydride reduction of the derived ketimines gives exo-bornylamines.
- Gamble, David L.,Hems, William P.,Ridge, Brian
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p. 248 - 260
(2007/10/03)
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- Dithiazoles and Related Compounds. Part 3. Preparation of 5H-1,4,2-Dithiazoles via 1,3-Dipolar Cycloadditions between Nitrile Sulphides and Thiocarbonyl Compounds, and some Conversions into 3,5-Diaryl-1,4,2-dithiazolium Salts
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Thermolysis of 1,3,4-oxathiazol-2-ones 3 in the presence of thiocarbonyl compounds gives modest to good yields of the little-known 5H-1,4,2-dithiazoles 1, the reaction being successful with diaryl, aryl alkyl and dialkyl ketones, and thiono esters, but failing with dithio esters and tertiary thioamides.The influence of substituents is discussed.Solvolysis of 5-ethoxy-5H-1,4,2-dithiazoles, derived from thiono esters, with perchloric acid in acetic anhydride gives high yields of 3,5-diaryl-1,4,2-dithiazolium salts 9.
- Wai, Kwok-Fai,Sammes, Michael P.
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p. 183 - 187
(2007/10/02)
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- Blue Copper Models. Synthesis and Characterization of Copper(II) Enethiolate Complexes derived from (1R)-3-Hydroxymethylenebornane-2-thione and 2-Aminothia-alkyl-1-methylbenzimidazoles (Donor Set N2SS*) or Diamines (Donor Set N2S2)
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A series of tetradentate ligands derived from the condensation of (1R)-3-hydroxymethylenebornane-2-thione and several 2-aminothia-alkylbenzimidazoles were synthesized together with their cationic zinc(II) and copper(II) complexes.While the free ligands exist in the thioxoenamine tautomeric form, binding to the metals occurs in their enethiolateimine form, as deduced from cumulative spectral evidence.The copper(II) complexes exhibit medium-intensity absorptions between 410 and 435 (ε 3500) and between 520 and 535 nm (ε 1200 dm3 mol-1 cm-1) attributable to enethiolate ?(S-) --> CuII and ?(S-) --> CuII ligand-to-metal charge transfer (l.m.c.t.) transitions, respectively, and relatively intense ligand-field transitions in the range 610-650 nm (ε 1500 dm3mol-1cm-1).All the bands undergo progressive red shift as the length of the carbon chain connecting the imine and thioether functions increases from two to four atoms.The frozen-solution e.p.r. spectra are indicative of progressive distortion towards a pseudo-tetrahedral geometry for copper(II) as the carbon chain length increases.A series of neutral copper(II) complexes derived from the condensation of (1R)-3-hydroxymethylenebornane-2-thione and symmetric diamines was also synthesized for comparison.Here too the length of the carbon chain connecting the imine nitrogen atoms was varied from two to four atoms.These complexes exhibit the same spectroscopic trends but with less marked distortion of the copper(II) chromophores as the length of the carbon chain increases.The cationi copper (II) complexes from (1R)-3-hydroxy-methylenebornane-2-thione and 2-aminothia-alkylbenzimidazoles display, in acetonitrile solution at -15 deg C, easy access to the corresponding copper(I) congeners (E0=-0.02V vs s.c.e.).By contrast, the neutral copper(II) species derived from (1R)-3-hydroxymethylenebornane-2-thione and diamines are reduced to the corresponding copper(I) complexes at potentials more negative by 0.7-1.0 V, depending upon the extent of stereochemical distortion around the copper(II) centre induced by the length of the imine-nitrogen-linking carbon chain.The planar complex bearing an ethylene bridging chain can be reversibly oxidized to the corresponding copper(III) species (E0= +0.37 V).
- Casella, Luigi,Gullotti, Michele,Suardi, Edoardo,Sisti, Massimo,Pagliarin, Roberto,Zanello, Piero
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p. 2843 - 2851
(2007/10/02)
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- Photochemical Oxidation of Thioketones: Steric and Electronic Aspects
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Oxidation of diaryl, aryl alkyl, and dialkyl thioketones by singlet oxygen generated via self-sensitization and other independent methods yielded the corresponding ketone and sulfine in varying amounts.A zwitterionic/diradical intermediate arising out of the primary interaction of singlet oxygen with the thiocarbonyl chromophore is believed to be the common intermediate for the ketone and sulfine.While closure of the zwitterion/diradical to give 1,2,3-dioxathietane would lead to the ketone, competing oxygen elimination is believed to lead to the sulfine.This partitioning is governed by steric and electronic factors operating on the zwitterionic/diradical intermediate.
- Ramnath, N.,Ramesh, V.,Ramamurthy, V.
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p. 214 - 222
(2007/10/02)
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- Reactions of Ketone Hydrazones and β-Keto Enamines with Disulfur Dichloride. New Synthesis of Thioketones and 5H-1,2,3-Dithiazoles
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Ketone hydrazones react with disulfur dichloride in the presence of triethylamine to afford thioketones in good yields.The reaction mechanism involving N-thiosulfinylamine (R2C=N-N=S=S) and S-thioxothioketone (R2C=S=S) is proposed.The formation of di-t-bu
- Okazaki, Renji,Inoue, Kaoru,Inamoto, Naoki
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p. 3541 - 3545
(2007/10/02)
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- Etude des spectres de masse des thiocetones cyclaniques et α-cyclaniques; mecanismes des fragmentations
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Twenty five cyclic and α-cyclic thioketones were examined by mass spectrometry.Compared with the oxygen analogues, the thioketones yielded a higher proportion of molecular ions.The loss of SH was found to be a characteristic fragmentation of cyclic and α-cyclic thioketones as for aliphatic thioketones.
- Paquer, D.,Morin, L.,Vazeux, M.,Andrieu, C. G.
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